Semiconductor device package and manufacturing method

ABSTRACT

A semiconductor device package includes a semiconductor device mounted and electrically coupled to a substrate, a package body encapsulating the semiconductor device against a portion of an upper surface of the substrate; and an electromagnetic interference shielding layer formed over the package body and substantially enclosing the semiconductor device. The electromagnetic interference shielding layer is a plated metal layer in contact with the package body, and the plated metal layer is connected to a ground trace extending on the upper surface of the substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.11/028,670 filed Jan. 5, 2005, entitled “SEMICONDUCTOR DEVICE PACKAGEAND MANUFACTURING METHOD THEREOF,” currently pending, herebyincorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to semiconductor device packages, and morespecifically to semiconductor device packages which are shielded toprotect against electromagnetic interference (EMI).

2. Description of the Related Art

Semiconductor device packages typically have electrical circuitryimplemented on a circuit substrate, such as a printed circuit board or aceramic substrate. The performance of the circuitry may be adverselyaffected by electromagnetic interference (EMI). Electromagneticinterference (EMI) is the generation of undesired electrical signals, ornoise, in electronic system circuitry due to the unintentional couplingof impinging electromagnetic field energy.

The coupling of signal energy from an active signal net onto anothersignal net is referred to as crosstalk. Crosstalk is within-system EMI,as opposed to EMI from a distant source. Crosstalk is proportional tothe length of the net parallelism and the characteristic impedancelevel, and inversely proportional to the spacing between signal nets.

Electronic systems are becoming smaller, and the density of electricalcomponents in these systems is increasing. As a result, the dimensionsof the average circuit element is decreasing, favoring the radiation ofhigher and higher frequency signals. At the same time, the operatingfrequency of these electrical systems is increasing, further favoringthe incidence of high frequency EMI. EMI can come from electricalsystems distant from a sensitive receiving circuit, or the source of thenoise can come from a circuit within the same system (crosstalk or nearsource radiated emission coupling). The additive effect of all thesesources of noise is to degrade the performance, or to induce errors insensitive systems.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to providesemiconductor device packages which are shielded to protect againstelectromagnetic interference (EMI).

To achieve the above listed and other objects, a semiconductor devicepackage having features of the present invention generally includes asemiconductor device mounted and electrically coupled to a substrate, apackage body encapsulating the semiconductor device against a portion ofan upper surface of the substrate; and an electromagnetic interferenceshielding layer formed over the package body and substantially enclosingthe semiconductor device. Preferably, the electromagnetic interferenceshielding layer is connected to ground potential, e.g., a ground traceextending on the upper surface of the substrate.

According to one aspect of the invention, the electromagneticinterference shielding layer may be a housing of electrically conductivethermoplastic or thermosetting compound which comprises a thermoplasticor thermosetting matrix and a plurality of conductive fillers compoundedtherewith. The housing may be securely attached to the package body viaan adhesive layer or directly mounted on the package body by an enforcedinserting method such that the housing fits tightly against and is incontact with the package body.

According to another aspect of the invention, the electromagneticinterference shielding layer may be a layer of conductive paint or anelectroless plated metal layer in contact with the package body.

According to another aspect of the invention, the electromagneticinterference shielding layer may be a metal cover securely attached tothe package body via an adhesive layer.

The present invention further provides a method for manufacturing thesemiconductor device package mentioned above. The method includes thefollowing steps: (a) attaching a plurality of semiconductor devices ontoa substrate strip including a plurality of substrate each having atleast one ground trace extending on an upper surface of the substrate;(b) electrically coupling the semiconductor devices to the substratestrip; (c) encapsulating the semiconductor devices against an uppersurface of the substrate strip to form a plurality of package bodieseach encapsulating one of the semiconductor devices on the substratestrip wherein each of the ground traces is positioned between twoadjacent package bodies; and (d) providing an electromagneticinterference shielding layer over each of the package bodies such thatthe electromagnetic interference shielding layer is connected to theground trace.

The present invention further provides another method for manufacturingthe semiconductor device package mentioned above. The method includesthe following steps: (a) electrically coupling the semiconductor devicesto the substrate strip; (b) encapsulating the semiconductor devicesagainst an upper surface of the substrate strip to form a moldedproduct; (c) conducting a singulation step to separate the moldedproduct into a plurality of individual molded units; and (d) providingan electromagnetic interference shielding layer over each of the moldedunits.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentinvention will be more fully understood by reading the followingdetailed description of the preferred embodiment, with reference made tothe accompanying drawings as follows:

FIG. 1A to 1C illustrate in cross-section major steps of fabrication ofa semiconductor device package according to one embodiment of thepresent invention;

FIG. 2A to 2C illustrate in cross-section major steps of fabrication ofa semiconductor device package according to another embodiment of thepresent invention;

FIG. 3A and FIG. 3B illustrate in cross-section major steps offabrication of a semiconductor device package according to anotherembodiment of the present invention;

FIG. 4A to 4C illustrate in cross-section major steps of fabrication ofa semiconductor device package according to another embodiment of thepresent invention;

FIG. 5A and FIG. 5B illustrate in cross-section major steps offabrication of a semiconductor device package according to anotherembodiment of the present invention;

FIG. 6A to 6C illustrate in cross-section major steps of fabrication ofa semiconductor device package according to another embodiment of thepresent invention;

FIG. 7 is a cross-sectional view of a semiconductor device packageaccording to another embodiment of the present invention; and

FIG. 8 is a cross-sectional view of a semiconductor device packageaccording to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1A to FIG. 1C illustrate a process for making a semiconductordevice package according to one embodiment of the present invention.

FIG. 1A shows four molded products 100 (only one is denoted in FIG. 1A)provided on a substrate strip 110. The substrate strip 110 comprises aplurality of substrates 112 (only one is denoted in FIG. 1A). Thoughonly four substrates 112 are shown in FIG. 1A, a substrate strip for usewith the invention can include any numbers of substrates that iscompatible with the manufacturing equipment, e.g., mold, being used.Each of the molded product 100 includes at least one semiconductordevice 120 attached to a substrate 112 by means of a conductive adhesive(not shown) such as a silver-filled epoxy or a non-conductive adhesive(not shown). The semiconductor device 120 is connected to the substrate112 by a plurality of bonding wires 130 which act as electricalinput/output (I/O) connections to a first set of contacts (not shown),e.g., conductive traces or pads, provided on the upper surface of thesubstrate 112. Alternatively, the semiconductor device 120 may beconnected to the substrate 112 by a plurality of solder balls. Thesolder balls may be formed on an active surface of the semiconductordevice 120 using one of any known bumping procedures. The upper surfaceof the substrate 112 is also provided with a second set of contacts (notshown) for electrical coupling to SMT devices 140. For making electricalconnection to an outside printed circuit board, the lower surface of thesubstrate is provided with a third set of contacts (not shown) which areelectrically interconnected to the first set of contacts and the secondset of contacts, and, usually, a plurality of solder balls (not shown)are mounted on the third set of contacts of the substrate 112. Thesubstrate strip 110 may be formed from a core layer made of fiberglassreinforced BT (bismaleimide-triazine) resin or FR-4 fiberglassreinforced epoxy resin thereby increasing the mechanical strength of thesubstrate strip 110.

As shown in FIG. 1A, each of the semiconductor devices 120 isencapsulated against the upper surface of the substrate strip 110 toform the aforementioned molded products 100. After encapsulating, eachof the semiconductor devices 120 is encapsulated in a package body 150.Thereafter, a singulation step is conducted to separate the assemblyshown in FIG. 1A into individual semifinished products (see FIG. 1B).

Thereafter, a housing 160 of electrically conductive thermoplastic orthermosetting compound is disposed on the package body 150 to reduce theamount of radiation which can penetrate therethrough thereby reducingthe total dose radiation received at the semiconductor device 120 to alevel less than the total dose tolerance of the semiconductor device120. Specifically, the electrically conductive thermoplastic orthermosetting compound may comprise a thermoplastic or thermosettingmatrix and a plurality of conductive fillers compounded therewith.Suitable conductive fillers for use with the present invention includestainless steel fibers, copper fibers, metal powders/particulates,nickel-coated graphite (NCG Fiber), and metal coated substrates(non-fiber) such as nickel-graphite powder, nickel-mica, or silver-glassbeads. The thermoplastic matrix may be formed from thermoplastic resinssuch as PP, PE, PS, ABS, EVA and PVC. Note that the housing according tothe present invention can be obtained in such a manner that theaforementioned conductive compound is pre-molded in a shape conform tothe contour of the package body 150. The housing 160 may be securelyattached to the package body 150 via an adhesive layer (not shown),preferably a conductive adhesive layer which may be formed by dipping ordispensing method.

Alternatively, the housing 160 may be directly mounted on the packagebody 150 by an enforced inserting method such that the housing 160 fitstightly against the package body 150 for securing the housing 160 inplace. In this embodiment, the housing 160 is in contact with thepackage body 150 and no adhesive layer is provided therebetween.

Preferably, the housing 160 is connected to ground potential.Specifically, the housing 160 may be secured to a ground trace 170extending on the upper surface of the substrate 112 by the conductiveadhesive layer mentioned above. The ground trace 170 is connected to oneindependent grounding portion (not shown) provided in the substrate 112by a dedicated vertical terminal such as via 180. The grounding portionmay be distributed in the substrate 112 in any available location, andare electrically joined to an electrical ground of an external printedcircuit (PC) main board (not shown) for supplying ground potential.

The substrate strip for use with the present invention may has a solderresist (not shown) formed thereon and the solder resist has openingsformed corresponding to the aforementioned contacts and the ground trace170 such that the contacts or ground trace 170 are exposed from thesolder resist.

FIG. 2A to FIG. 2C illustrate a process for making a semiconductordevice package according to another embodiment of the present invention.

After the semiconductor devices 120 and the SMT devices 140 arerespectively mounted to the substrates 212 and a regular wire-bondingprocess is performed to make interconnections between the devices 120and the substrates 212, all of the semiconductor devices 120 and the SMTdevices 140 are encapsulated against the upper surface of a substratestrip 210 to form a molded product 200 (see FIG. 2A). Afterencapsulating, all of the semiconductor devices 120 including and theSMT devices 140 are encapsulated in a package body 250. Usually, a MAP(mold array package) molding process is used to accomplish thisencapsulation. Thereafter, post-mold curing and singulation steps wereconducted to obtain an individual molded unit as shown in FIG. 2B. Inthe singulation process, a resin-bond saw blade is used to cut themolded product 200 shown in FIG. 2A into individual molded units alongpredetermined dicing lines (e.g., dashed lines shown in FIG. 2A).

Thereafter, a housing 260 of electrically conductive thermoplastic orthermosetting compound is disposed on the package body 250 for providingEMI shielding. Specifically, the housing 260 is formed in such a mannerthat the aforementioned conductive compound is pre-molded in a shapeconform to the contour of the molded unit shown in FIG. 2B. As shown inFIG. 2C, the housing 260 has a main body 260 a and a side wall 260 bextending from the main body 260 a, and the bottom of the side wall 260b is flush with the lower surface of the substrate 212. The housing 260may be securely attached to the molded unit shown in FIG. 2B via anadhesive layer (not shown), preferably a conductive adhesive layer.

Alternatively, the housing 260 may be directly mounted on the moldedunit shown in FIG. 2B by an enforced inserting method such that thehousing 260 fits tightly against the molded unit shown in FIG. 2B forsecuring the housing 260 in place. In this embodiment, the housing 260is in contact with the package body 150 and no adhesive layer isprovided therebetween.

Preferably, the housing 260 is connected to ground potential.Specifically, the housing 260 may be connected to one independentgrounding portion (not shown) provided in the substrate 212. Thegrounding portion may be distributed in the substrate 212 in anyavailable location, and are electrically joined to an electrical groundof an external printed circuit (PC) main board (not shown) for supplyingground potential. Alternatively, the bottom of the side wall 260 b ofthe housing 260 may be directly connected to an electrical ground of anexternal printed circuit (PC) main board (not shown).

FIG. 3A and FIG. 3B illustrate a process for making a semiconductordevice package according to another embodiment of the present invention.Referring to FIG. 3A, a conductive paint layer 310, e.g., a conductiveink layer, is directly formed over the molded products 100 and a portionof the substrate strip 110 for providing EMI shielding. The moldedproducts 100 and the substrate strip 110 are identical to those shown inFIG. 1A, and will not be described hereinafter in further detail. Theconductive paint layer 310 may be applied in the same manner to commonpaints by using a spray gun (or a brush) or via a dipping step. Theconductive paint includes conductive fillers such as carbon black or anyconductive metal (most commonly copper, nickel, silver, and combinationsthereof) mixed with a nonconductive carrier. Note that the conductivepaint layer 310 may be replaced with an electroless plated metal layer.

Thereafter, a singulation step is conducted to separate the assemblyshown in FIG. 3A into individual semiconductor device packages (see FIG.3B). Preferably, the conductive paint layer 310 is connected to groundpotential in a manner substantially identical to that described withreference to FIGS. 1A to 1C.

FIG. 4A to FIG. 4C illustrate a process for making a semiconductordevice package according to another embodiment of the present invention.After a saw blade is used to cut the molded product 200 shown in FIG. 4Ainto individual molded units shown in FIG. 4B along predetermined dicinglines (e.g., dashed lines shown in FIG. 4A), a conductive paint layer410 is respectively formed over the molded units shown in FIG. 4B forproviding EMI shielding. The molded product 200 and the substrate strip210 are identical to those shown in FIG. 2A, and will not be describedhereinafter in further detail. The conductive paint layer 410 may beapplied in the same manner as described above except that the conductivepaint layer 410 has a main body 410 a and a side wall 410 b extendingfrom the main body 410 a, and the bottom of the side wall 410 b is flushwith the lower surface of the substrate 212. Note that the conductivepaint layer 410 may be replaced with an electroless plated metal layer.Preferably, the conductive paint layer 410 is connected to groundpotential in a manner substantially identical to that described withreference to FIGS. 2A to 2C.

FIG. 5A and FIG. 5B illustrate a process for making a semiconductordevice package according to another embodiment of the present invention.Referring to FIG. 5A, a plurality of metal covers 510 are securelyattached to the package bodies 150 via adhesive layers 520 for providingEMI shielding, respectively. The molded products 100 and the substratestrip 110 are identical to those shown in FIG. 1A, and will not bedescribed hereinafter in further detail. The metal cover 510 may be madeof any conductive metal (most commonly copper, nickel, silver, andcombinations thereof). Note that the adhesive layer 520 may be replacedby a double-coated adhesive tape comprised of a polymer film coated onboth sides with adhesive. Thereafter, a singulation step is conducted toseparate the assembly shown in FIG. 5A into individual semiconductordevice packages (see FIG. 5B). Preferably, the metal cover 510 isconnected to ground potential in a manner substantially identical tothat described with reference to FIGS. 1A to 1C. Alternatively, themetal cover 510 may be secured to the ground trace 170 on the substrate112 by a soldering interface (e.g., Au—Sn solder), a conductive adhesiveinterface, or resistance welding.

FIG. 6A to FIG. 6C illustrate a process for making a semiconductordevice package according to another embodiment of the present invention.After a saw blade is used to cut the molded product 200 shown in FIG. 6Ainto individual molded units shown in FIG. 6B along predetermined dicinglines (e.g., dashed lines shown in FIG. 6A), a plurality of metal covers610 (see FIG. 6C) are securely attached to the package bodies 250 viaadhesive layers 620 for providing EMI shielding, respectively. Themolded product 200 and the substrate strip 210 are identical to thoseshown in FIG. 2A, and will not be described hereinafter in furtherdetail. The metal cover 610 is substantially identical to the metalcover 510 mentioned above except that the metal cover 610 has a mainbody 610 a and a side wall 610 b extending from the main body 610 a, andthe bottom of the side wall 610 b is flush with the lower surface of thesubstrate 212. Preferably, the metal cover 610 is connected to groundpotential in a manner substantially identical to that described withreference to FIGS. 2A to 2C.

FIG. 7 shows a semiconductor device package according to anotherembodiment of the present invention mainly including a semiconductordevice 120 attached to a substrate 212 by means of a conductive adhesive(not shown). The semiconductor device 120 is connected to the substrate212 by a plurality of bonding wires 130 which act as electricalinput/output (I/O) connections to a first set of contacts (not shown),e.g., conductive traces or pads, provided on the upper surface of thesubstrate 212. Alternatively, the semiconductor device 120 may beconnected to the substrate 212 by a plurality of solder balls. The uppersurface of the substrate 112 is also provided with a second set ofcontacts (not shown) for electrical coupling to SMT devices 140. Formaking electrical connection to an outside printed circuit board, thelower surface of the substrate is provided with a third set of contacts(not shown) which are electrically interconnected to the first set ofcontacts and the second set of contacts, and, usually, a plurality ofsolder balls (not shown) are mounted on the third set of contacts of thesubstrate 212.

As shown in FIG. 7, the semiconductor device 120 is encapsulated in apackage body 250 against the upper surface of the substrate 212. Thepackage body 250 has a side surface flush with a side surface of thesubstrate 212, so as to define a coplanar side surface. A plated metallayer 710, e.g., an electroless plated metal layer, is formed over thepackage body 250 and substantially encloses the semiconductor device 120thereby acting as an electromagnetic interference shielding layer toreduce the amount of radiation which can penetrate therethrough.Preferably, the plated metal layer 710 has a main body 710 a and a sidewall 710 b extending from the main body 710 a, and the bottom of theside wall 710 b is flush with the lower surface of the substrate 212.The side wall 710 b of the plated metal layer 710 is disposed on andparallel to the coplanar side surface defined by the side surface of thepackage body 250 and the side surface of the substrate 212. Note thatthe plated metal layer 710 is connected to a ground trace 720 extendingon the upper surface of the substrate 112. The ground-trace 720 of thesubstrate has a portion exposed on the coplanar side surface (defined bythe side surface of the package body 250 and the side surface of thesubstrate 212) for connecting to the plated metal layer 710. The exposedportion of the ground trace 720 is sandwiched between the side surfaceof the package body 250 and the side surface of the substrate 212. Theground trace 720 is connected to one independent grounding portion (notshown) provided in the substrate 212 by a dedicated vertical terminalsuch as via 722. The grounding portion may be distributed in thesubstrate 212 in any available location, and are electrically joined toan electrical ground of an external printed circuit (PC) main board (notshown) for supplying ground potential.

FIG. 8 shows a semiconductor device package according to anotherembodiment of the present invention. The semiconductor device package ofFIG. 8 is substantially identical to the semiconductor device package ofFIG. 7 except that the bottom of the side wall 810 b of the plated metallayer 810 is in contact with the upper surface of the substrate 212instead of flushing with the lower surface of the substrate 212. Inaddition, the side wall 810 b of the plated metal layer 810 is flushwith the side surface of the substrate 212, so as to define a coplanarside surface.

Although the invention has been explained in relation to its preferredembodiments, it is to be understood that many other possiblemodifications and variations can be made without departing from thespirit and scope of the invention as hereinafter claimed.

1. A semiconductor device package comprising: a substrate having atleast one ground trace extending on an upper surface thereof; asemiconductor device mounted and electrically coupled to the substrate;a package body encapsulating the semiconductor device against a portionof the upper surface of the substrate; and an electromagneticinterference shielding layer formed over the package body andsubstantially enclosing the semiconductor device; wherein theelectromagnetic interference shielding layer is a plated metal layer incontact with the package body and in contact with the upper surface ofthe substrate, and the plated metal layer is connected to the groundtrace; and wherein the plated metal layer has a main body and a sidewall extending from the main body, and the bottom of the side wall is incontact with the upper surface of the substrate, while the side wall ofthe plated metal layer is flush with a side surface of the substrate, soas to define a coplanar side surface.
 2. The semiconductor devicepackage as claimed in claim 1, wherein the plated metal layer is anelectroless plated metal layer.
 3. The semiconductor device package asclaimed in claim 1, further comprising a SMT device mounted on the uppersurface of the substrate and encapsulated in the package body and theelectromagnetic interference shielding layer.
 4. The semiconductordevice package as claimed in claim 1, wherein the package body has aside surface that is laterally recessed relative to the side surface ofthe substrate.
 5. The semiconductor device package as claimed in claim4, wherein the side surface of the package body is laterally recessed byan amount corresponding to a thickness of the side wall of the platedmetal layer.
 6. The semiconductor device package as claimed in claim 1,wherein the substrate includes a via at least partially extendingbetween the upper surface of the substrate and a lower surface of thesubstrate, and the ground trace is connected to the via.